functions of the skeletal system
support
storage of minerals and lipids
blood cell production: red marrow produces blood cells
protection
leverage: many bones function as levers
long bones
long and slender
located in arm, forearm, thigh, leg, fingers, etc.
short bones
boxy
examples: carpal bones and tarsal bones
flat bones
thin, flat bones
examples: bones that form the roof of the skeleton, ribs, scapula
irregular bones
complex shapes
examples: vertebrae, bones of the pelvis
sesamoid bones
generally small, flat, irregular shaped bones
develop inside tendons and commonly located near joints
example: patellar shape
sutural bones (wormian bones)
small, flat, irregular shaped bones
located between flat bones of the skull
epiphysis
part of long bone; end of the long bone
diaphysis
part of long bone; long, tubular shaft
metaphysis
part of long bone; connects the epiphysis to the diaphysis
articular (hyaline) cartilage
part of long bone; covers the epiphysis and cushions the opposing bone ends during joint movement
spongy (cancellous) bone
part of long bone; forms an open network of struts and plates in the interior of a bone
compact bone
part of long bone; dense outer layer of bone that forms a sturdy, protective layer
epiphyseal line
part of long bone; where the epiphyseal plate used to be
epiphyseal plate
a disc of hyaline cartilage that grows during childhood to lengthen the bone
periosteum
part of long bone; two-layered membrane that covers the outside of a bone
richly supplied with nerve fibers, lymphatic vessels and blood vessels
marrow/medullary cavity
part of long bone; central space of the bone
contains yellow marrow in adults
endosteum
part of long bone; covers the spongy bone in the marrow cavities and lines the canals that pass through compact bone
cortex
part of flat, short and irregular bone; layers of compact bone surrounding the spongy bone in a flat bone
diploe
part of flat, short and irregular bone; internal layer of spongy bone
osteon
part of compact bone; structural unit of compact bone consisting of bone matrix arranged in concentric circles around a central canal
central canal
part of compact bone; contains one or more blood vessels that carry blood through a single osteon
perforating canal
part of compact bone; lie at right angles to the long axis of bone and connect the blood and nerve supply to osteons deeper in the bone and to tissues of the marrow cavity
canaliculi
part of compact bone; connect the lacunae to each other and allows osteocytes to communicate through the hard bone matrix
trabeculae
part of spongy bone; a honeycomb of small needle-like or flat pieces
osteoblasts
cell in bone tissue; produce new bone matrix
osetocytes
cell in bone tissue; mature bone cells that maintain the bone matrix
osteoclasts
cell in bone tissue; giant cells that remove bone matrix by secreting protein-digesting enzymes
osteoprogenitor cells
cell in bone tissue; mesenchymal stem cells that divide and can differentiate into osteoblasts
maintain populations of osteoblasts and are important in the repair of a fracture
hydroxyapatite
inroganic material in bone matrix
substances that make up hydroxyapatite
calcium and phosphate
function of hydroxyapatite
makes the bone hard and brittle
collagen fibers
organic material in bone matrix
function of collagen fibers
make the bone flexible and able to withstand twisting/bending